Intermittent Cable Internet Issue

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Intermittent Cable Internet Issue

Postposted on Mon Jun 10, 2013 3:27 pm

So, here is the symptom.
Internet randomly dies, has poor performance, and most websites will no longer open. But it doesn't die completely. When it's having issues, my pings to google's DNS servers drop, while pings to level3's DNS servers work just fine or vise versa. Other time OpenDNS's DNS server pings fine while Level3's doesn't. Other times cableone's DNS server doesn't ping okay while google's work okay. This happens several times a day, and packet dropping persists for about 20-50 seconds, then about 20-50 seconds of it working with normal latency, and then drop packets again. This occurs for about 5-10 minutes. Sometimes the latency climbs to about 150ms from the normal 30ms during the 20-50 seconds on the internet working while it's having problems.

Here is what I did, and some info.
I have used several different routers, and the problem persists.
My cable modem's SnR is 34-37db. The average is 36db and this number does not change even when the internet is having problems.
Upstream power is about 37-39db and downstream power is -2-0db, so the numbers look okay, and again these numbers stay the same even during internet problems.
There is also no sign of the routers or the modem restarting.

When I used the tracert tool during the times when the internet is having issues, I noticed that the 4th hop (looks like one of cable one's nodes) have high latency or drops packets. Normally its about 10ms for that hop, but when the problem occurs, it climbs to 150-250ms or drops the packet.

So, what's going on with my internet? and cable one has no clue either.

My guess is that one of the neighborhood node is failing but if that is the case then why am I able to ping one DNS server and not the other? Does a failing cable node cause problems like this? Last time one of the node's connections were failing, everything died and I wasn't able to connect to any DNS server and my SnR dropped to about 10.

I really wish I can get FIOS where I live....There is DSL available but my past experience with DSL makes me really leery about that option.
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Re: Intermittent Cable Internet Issue

Postposted on Mon Jun 10, 2013 3:47 pm

Change your DNS to OpenDNS and take the ISP DNS issues right out of play. Use the router's property pages to hard-code those two DNS addresses and let all of the downstream devices grab them through DHCP.
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Re: Intermittent Cable Internet Issue

Postposted on Mon Jun 10, 2013 4:04 pm

I tried that but for some reason the new settings don't "stick". On the status page it still shows the cable company's DNS servers. I'm using openDNS using my computer's internet settings. The router I'm using is the Linksys WRT54GL with the latest firmware on it.
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Re: Intermittent Cable Internet Issue

Postposted on Mon Jun 10, 2013 4:12 pm

CB5000 wrote:I tried that but for some reason the new settings don't "stick". On the status page it still shows the cable company's DNS servers. I'm using openDNS using my computer's internet settings. The router I'm using is the Linksys WRT54GL with the latest firmware on it.

Throw Tomato on it and don't look back. I've been running it on my 54GL for at least a couple of years with no issues whatsoever. Also adds some nice access restriction capabilities that are much easier to navigate than stock Linksys firmware. Also may want to go into the modem settings and make sure it isn't acting as a DHCP server. If it's supplied by your ISP, it just might be. A quick upgrade to a Motorola SB6121 can fix that.

http://www.polarcloud.com/tomato

EDIT: My Motorola tells me the range of addresses it'll try to serve using DHCP, namely 192.168.100.11 through .42. Make sure your router and downstream devices are on a different subnet (I always set the router to 192.168.1.1) to keep the modem from interfering.
There are people that embrace the Oxford comma and people who don't. Never get between these people when drink has been taken. I use the Oxford comma and always will. The rest can sod off.
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Re: Intermittent Cable Internet Issue

Postposted on Mon Jun 10, 2013 4:22 pm

Hmm, I'll try that tomato firmware, looks pretty spiffy :)

Simple question: when you upgrade to a new modem, you need to let the cable company know the mac address on the modem right? I seem to remember doing that eons ago... I'm still using the old SB5100 I bought like 8 years ago.

So you think it might be that cable one's DNS servers are being flaky and are interfering with the internet connection?
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Re: Intermittent Cable Internet Issue

Postposted on Mon Jun 10, 2013 4:33 pm

CB5000 wrote:Hmm, I'll try that tomato firmware, looks pretty spiffy :)

Simple question: when you upgrade to a new modem, you need to let the cable company know the mac address on the modem right? I seem to remember doing that eons ago... I'm still using the old SB5100 I bought like 8 years ago.

So you think it might be that cable one's DNS servers are being flaky and are interfering with the internet connection?

Yes and no. Their DNS may be flaky, but I also think your router might be in the modem's DHCP address space thus causing the modem to force the ISP DNS addresses to your router and bypassing your attempts to get around the flaky servers. Motorola modems are always 192.168.100.1. Make sure your router is not 100 in the third quad.

Reprovisioning a modem should be a 2-minute call to your ISP. If they have an approved modem list on their website, make sure to follow it. That said, it'd be rare that a Motorola wasn't on the list.
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Re: Intermittent Cable Internet Issue

Postposted on Mon Jun 10, 2013 5:26 pm

My router is set at 192.168.1.1, and my wireless router is set at 192.168.2.1 so it should be fine. Pretty sure that SB6121 is on the approved list, but I don't think the modem is necessarily broken, just old.

This problem only started about a week ago and getting worse, nothing on my setup changed in months so It might be a problem with Cable One's network.

Okay here is one example of the node? lagging during problematic internet connectivity.
Code: Select all
  5   173 ms   226 ms     *     192.168.102.209
  5   107 ms   223 ms   200 ms  192.168.102.209
  5    39 ms    13 ms    34 ms  192.168.102.209
  5    14 ms    12 ms    37 ms  192.168.102.209
  5    10 ms    38 ms    34 ms  192.168.102.209
  5    48 ms    22 ms     9 ms  192.168.102.209
  5    11 ms     9 ms     9 ms  192.168.102.209

First two lines are the times when the internet was barely working and even showing a dropped packet, and subsequent traces showing improving latency as the problem goes away.

I'm not sure what 192.168.102.209 is. It occurs at the 5th hop so I think it's one of cable one's neighborhood node?
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Re: Intermittent Cable Internet Issue

Postposted on Mon Jun 10, 2013 5:37 pm

192.168.102.209 is not an externally-routable address.
There are people that embrace the Oxford comma and people who don't. Never get between these people when drink has been taken. I use the Oxford comma and always will. The rest can sod off.
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Re: Intermittent Cable Internet Issue

Postposted on Mon Jun 10, 2013 7:15 pm

Yeah I know, that's why I think it's one of cable one's nodes which are not external.
Here is the full tracert to google's DNS when the internet is being flaky. First 2 are my routers, then hop 3 is probably the cable box outside, then the next 2 are cable one's nodes. 6-14 are all external outside cable one's networks.
Code: Select all
  1     2 ms    <1 ms    <1 ms  192.168.1.1
  2     1 ms     1 ms     1 ms  192.168.2.1
  3    11 ms    21 ms    11 ms  10.107.136.1
  4    10 ms    42 ms    11 ms  192.168.62.89
  5   173 ms   226 ms     *     192.168.102.209
  6    20 ms    20 ms    19 ms  xe-8-1-2.edge2.Seattle1.Level3.net [4.53.158.9]
  7    20 ms    19 ms    24 ms  ae-2-52.edge1.Seattle3.Level3.net [4.69.147.170]
  8    36 ms    26 ms    21 ms  GOOGLE-INC.edge1.Seattle3.Level3.net [4.59.232.30]
  9    19 ms    20 ms    47 ms  209.85.249.34
 10    35 ms    61 ms    26 ms  66.249.94.197
 11    27 ms    40 ms    27 ms  216.239.46.200
 12     *        *       34 ms  216.239.48.165
 13     *        *        *     Request timed out.
 14    32 ms    30 ms    30 ms  google-public-dns-a.google.com [8.8.8.8]


Here is the same trace when the internet works okay
Code: Select all
  1    <1 ms    <1 ms    <1 ms  192.168.1.1
  2     1 ms     1 ms     1 ms  192.168.2.1
  3     9 ms    19 ms     8 ms  10.107.136.1
  4    10 ms    10 ms     9 ms  192.168.62.89
  5     9 ms    15 ms    18 ms  192.168.102.209
  6    45 ms    34 ms    22 ms  xe-8-1-2.edge2.Seattle1.Level3.net [4.53.158.9]
  7    24 ms    27 ms    21 ms  ae-2-52.edge1.Seattle3.Level3.net [4.69.147.170]
  8    22 ms    20 ms    19 ms  GOOGLE-INC.edge1.Seattle3.Level3.net [4.59.232.30]
  9    25 ms    28 ms    20 ms  209.85.249.34
 10    20 ms    20 ms    23 ms  66.249.94.201
 11    37 ms    28 ms    31 ms  216.239.46.208
 12    26 ms    26 ms    38 ms  216.239.48.165
 13     *        *        *     Request timed out.
 14    27 ms    29 ms    38 ms  google-public-dns-a.google.com [8.8.8.8]
CB5000
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Re: Intermittent Cable Internet Issue

Postposted on Mon Jun 10, 2013 7:21 pm

Looks like your ISP is running several levels of NAT because they only have one external IPv4 addy for an entire block or the like. One time that living in rural VT is FTW.
There are people that embrace the Oxford comma and people who don't. Never get between these people when drink has been taken. I use the Oxford comma and always will. The rest can sod off.
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Re: Intermittent Cable Internet Issue

Postposted on Mon Jun 10, 2013 7:47 pm

Yeah... the hazards of rural living -_-....
CB5000
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Re: Intermittent Cable Internet Issue

Postposted on Tue Jun 11, 2013 7:09 pm

The cable one's tech support people are absolutely useless.

They don't even understand what traceroute, node, ping, or any of the network jargon mean.

How do I convince them that the problem is on their end?

When my net dies the connection ends at 192.168.102.209, which is the final node facing the internet on cable one's internal network... And yet they want me to buy a new modem, new routers, and sell me crap.
The problem is getting worse, since this time it won't even connect beyond that. When hop 16 came around, the internet momentarily started working again.
Code: Select all
tracert 4.2.2.2

Tracing route to b.resolvers.Level3.net [4.2.2.2]
over a maximum of 30 hops:

  1    <1 ms     2 ms    <1 ms  192.168.1.1
  2     1 ms     2 ms     1 ms  192.168.2.1
  3    11 ms    10 ms    16 ms  10.107.136.1
  4    12 ms    13 ms    10 ms  192.168.62.89
  5    18 ms    10 ms    11 ms  192.168.102.209
  6     *        *        *     Request timed out.
  7     *        *        *     Request timed out.
  8     *        *        *     Request timed out.
  9     *        *        *     Request timed out.
 10     *        *        *     Request timed out.
 11     *        *        *     Request timed out.
 12     *        *        *     Request timed out.
 13     *        *        *     Request timed out.
 14     *        *        *     Request timed out.
 15     *        *        *     Request timed out.
 16    39 ms    43 ms    36 ms  b.resolvers.Level3.net [4.2.2.2]


I even told him that they need to check whatever node 192.168.102.209 is and make sure it's running okay and he basically acts like I'm talking in some alien language. I know the problem is there because I can always ping to openDNS's servers and guess what it uses a different node that's probably not broken.... 192.168.102.221
Code: Select all
tracert 208.67.222.222

Tracing route to resolver1.opendns.com [208.67.222.222]
over a maximum of 30 hops:

  1    <1 ms    <1 ms     2 ms  192.168.1.1
  2     1 ms     1 ms     1 ms  192.168.2.1
  3    29 ms     9 ms    11 ms  10.107.136.1
  4    57 ms    11 ms    36 ms  192.168.62.89
  5     9 ms    55 ms    27 ms  192.168.102.221
  6    31 ms    77 ms    28 ms  4.53.158.1
  7    30 ms    88 ms    39 ms  OPEN-DNS-IN.edge2.Seattle1.Level3.net [4.53.159.226]
  8    20 ms    39 ms    21 ms  resolver1.opendns.com [208.67.222.222]
Trace complete.

Sorry if I sound annoyed, but the tech support person was really annoying me.
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Re: Intermittent Cable Internet Issue

Postposted on Mon Jun 17, 2013 11:42 am

So an update:
After probing for information from Cable One and other cable one customers (who had similar issues), it turns out that Cable One was doing a series of unannounced maintenance and "upgrades" to their network over the past few weeks which would explain changes to the node IP addresses over time when using the tracert tool. Then a few days ago, they updated their website to show their new internet service plans, and the intermittent connectivity issues stopped.

According to their policy, they are only allowed to do network disrupting maintenance during the hours of 1am-5am or something like that, but they were doing it all times of the day. Cable One of course denies that the maintenance could cause connectivity issues.

I really wish that some day internet will be regulated like a utility, so we are not at the mercy of the local cable monopoly.
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